Epigenetic regulation of stress responses in plants

Abstract

Gene expression driven by developmental and stress cues often depends on nucleosome histone post-translational modifications and sometimes on DNA methylation. A number of studies have shown that these DNA and histone modifications play a key role in gene expression and plant development under stress. Most of these stress-induced modifications are reset to the basal level once the stress is relieved, while some of the modifications may be stable, that is, may be carried forward as 'stress memory' and may be inherited across mitotic or even meiotic cell divisions. Epigenetic stress memory may help plants more effectively cope with subsequent stresses. Comparative studies on stress-responsive epigenomes and transcriptomes will enhance our understanding of stress adaptation of plants.

Figure 1

Epigenetic regulation of stress tolerance. Primary and secondary stress signals induce changes in the expression and/or activity of epigenetic regulators namely, small RNAs, RdDM components, histone variants, histone modification enzymes, and chromatin remodeling factors. These epigenetic regulators modify histone variants, histone modifications, and DNA methylation. Some of these are heritable epigenetic modifications, while others are transient changes. Transient chromatin modifications mediate acclimation response. Heritable epigenetic modifications provide within-generation and transgenerational stress memory.